The heart muscle’s function is to pump blood through the body. The pump is controlled by an electrical system that generates each pulsation. Every cell in the heart muscle is capable of initiating an electrical impulse or a “heartbeat”. Although there are specific pacemaker cells whose responsibility is to generate each heartbeat, and respond to exercise and fever by increasing the heart rate, it is normal to have occasional extra beats which originate in the top of the heart (the atrium) or the bottom of the heart (the ventricle). Everyone has occasional extra beats, and at times they can occur frequently under normal conditions. These irregular or extra heart beats cause a sensation called palpitation.
Patients describe palpitations as fullness in the throat or neck, or a more forceful, heavy beat. Sometimes patients feel atypical chest pain with palpitations. People often experience palpitations in the evening when they are reading or watching television, or at night when they get into bed. This is not because the frequency of arrhythmias is greater at night, but rather the mind and body are relaxing at this time and are more susceptible to becoming aware of the symptoms. The sensation of irregularity of the heartbeat can cause anxiety which produces an increase in the adrenaline level. This rise in adrenaline level can, in turn, increases the frequency of the premature beats, making the palpitations worse, and a vicious cycle ensues.
The other causes of rapid heart beats which originate in the top of the heart (the atrium) are atrial fibrillation and supra-ventricular tachycardia (known as SVT). These arrhythmias cause the heart to race rapidly or irregularly. They can start and stop suddenly. The rapid or irregular heartbeat can last several hours or can be very short in duration. In the past, some patients with this type of arrhythmia were diagnosed with panic disorders or anxiety and treated, wrongly, with sedatives. There are also sustained or non-sustained arrhythmias which originate in the bottom of the heart called ventricular tachycardia which usually require a careful, thorough evaluation. Today we are more aware of the prevalence of arrhythmias and have improved tools for arrhythmia diagnosis. Rapid and/or irregular sustained arrhythmias should be evaluated by a physician and can usually be treated simply and easily.
Arrhythmias are classified based on the presence or absence of underlying structural heart disease. In the absence of structural heart disease, most arrhythmias are benign and do not have an impact on longevity but they can cause disabling symptoms. In the case of underlying heart disease, careful work up of arrhythmias is required to prevent life threatening consequences. In some cases, arrhythmias herald the presence of new heart disease. All arrhythmia evaluations include assessment of the heart muscle function. In patients with structural heart disease, the cardiologist is given the opportunity to intervene on behalf of arrhythmia management and prevent potentially life threatening complications.
In women, all types of arrhythmias are worse during the bleeding phase of the menstrual cycle and during pregnancy. The perception that arrhythmias or palpitations are "hormonal” is accurate.
What should I do?
If you experience frequent palpitations or irregularities in your heartbeat, you should consult your physician. Keep in mind that 80-90% of palpitations are benign and after work-up can ultimately be treated with reassurance or a low dose of medication.